Animal World

Animal Characteristics and Activities

Can animals regenerate parts of their bodies?

Regeneration does occur in some animals; however, it progressively declines the more complex the animal species becomes. Among primitive invertebrates (lacking a backbone), regeneration frequently occurs. For example, a planarium (flatworm) can split symmetrically, each part becoming a clone of the other. In higher invertebrates regeneration occurs in echinoderms (such as starfish) and arthropods (such as insects and crustaceans). Regeneration of appendages (limbs, wings, and antennae) occurs in insects (such as cockroaches, fruit flies, and locusts) and in crustaceans (such as lobsters, crabs, and crayfish). For example, regeneration of the crayfish’s missing claw occurs at its next molt (shedding of its hard cuticle exterior shell/skin for the growing and the subsequent hardening of a new cuticle exterior). However, sometimes the regenerated claw does not achieve the same size of the missing claw. But after every molt (occurring two to three times a year) it grows and will eventually become nearly as large as the original claw. On a very limited basis, some amphibians and reptiles can replace a lost leg or tail.